To investigate the hypothesis that asthma is genetically determined on the basis of transcriptional dysregulation of genes associated with development of the disease. To investigate linkages to candidate genes present on the long arm of chromosome 5, which includes the genes for interleukins-3, -4, -5, -9, and GM-CSF. Activities of these genes include mast cell differentiation, eosinophilic growth and activation, macrophage and T cell activation, and the EGE isotype switch.